U.S. Treasury Undersecretary David Cohen, in charge of terrorism and financial intelligence, was in South Korea Wednesday for talks on North Korea, which is already facing tightened U.N. Security Council sanctions for its Feb. 12 nuclear test.

Since then, North Korea, an isolated, impoverished Communist country, has been issuing provocative threats against the United States and South Korea, including preemptive nuclear strikes.

Cohen, who arrived in Seoul Tuesday, was quoted as saying he would ask South Korea to join the U.S. sanctions.

"We are going to discuss with the government of South Korea about a whole range of possible issues to recent actions by North Korea," Cohen told Yonhap, adding it would be up to the Seoul government to decide how it wants to respond.

U.S. has already imposed its own sanctions on the Foreign Trade Bank of North Korea, the Communist country's main foreign exchange institution.

Earlier, Yonhap, quoting several sources, said Cohen and Dan Fried, the U.S. State Department's sanctions coordinator, on their current Asia trips have been discussing ways to impose financial restrictions on North Korea similar to those faced by Iran. Their trips would include a visit to China.

"It is unusual that China accepted a simultaneous trip by two ranking U.S. government officials handling sanctions on North Korea," one source told Yonhap.

A diplomatic source was quoted as saying the trips by Cohen and Fried may itself send a message to North Korea.

Separately, Kyodo News, quoting sources, said the Japanese government plans to stop its financial institutions from doing business with North Korea's Foreign Trade Bank as a way to cooperate closely with the United States over the North Korean nuclear threat.

The report said although there are currently no transactions between Japanese institutions and the North Korean bank, it is hoped a formal sanction would encourage other countries, including those in China, to bring more pressure on the North.

Kyodo said Japanese Finance Ministry and Foreign Ministry officials had separately informed Cohen about the plan during his Japan visit.

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